3d projection plane

Hi, i have a before-i-m-using-vvvv show wich is reborning.

Here is a video: http://www.dailymotion.com/video/x70wxv_princesse-beau-geste_creation

The projection is simple: one vp on ground projecting inside a trapezoidal box. All the compositing was done for the length from vp to box , with masks inside and its optic
All video was edited and composed for this ratio of distance and angle.
Its only flat quad projected
I would like to avoid 3d software to edit this trapezoidale box directly.
I would like to know if there is any way to recreate in vvvv a mesh simply for this and compense by camera position a new distance and angle .
The ground doesn t matter , there is 4 spaces of projection: center, sides and top

Should i use the grid or a bundle of quads ?

hi karistouf
dont know if homography helps you
arrange your texture according your needs

myhomography.v4p (15.3 kB)

hi DiMiX, nice to read you ;-)
hum i will surely use homography for something else. but helas not that one.
i cant focus enough texture correctly ( texture transform pin of the quad) to obtain the global image being one.

i put here some snapshot of the source itself, showing edge. but there are a lot of things working on the general image also, passing from one plane to the other.

i think you will not be able to get nice multi-“keystone” correction with ONE grid, i would do it with group of 4 grids

hi DiMiX, yes i have played around a bit with it.
i agree with you totally. i will try tomorow to see if i can find solution. its maybe by using keying that i could sort this… on 4 crops of the original image using at end homography on the 4 outputted textures…


hi daniel, thxs for link, but grid editor is ok only on a normal image. the project i m reborning quickly contains in its video already masks and deformations. thats the trick ;-)

I can see the masks, but I don’t see the deformations. The images above all are flat, just masked for the four surfaces. So is the issue that the mask lines were assuming a certain projection geometry, correct?

Have you tested the new projector position and know there is a noticeable problem? If the projectors are a normal/long distance away, I would think you could move them quite a bit (closer/farther) without seeing much difference. Particularly if you took care to align the back wall lines, you should be able to mask spill around the outer edges. I like to try the low-tech approaches first!

Aha! Check out girlpower(slide projector) - it should work. Build your box with four quads, “project” your video on to it using the old projector position, and set your camera to the new projector position.

hi mediadog, you are damned right, no deformation ;-)
flat img.

ok i take a look to it and come back ;-) nice to read you ;-)

thxs mediadog, the old projector node is the better result i can have. i must wait now for reherasals with the decor to test it ;-)